1. Technical Field
The present invention relates to a drug dispensing apparatus for dispensing drugs contained in a cassette one by one, more specifically to a drug dispensing apparatus in which present quantity of the drugs contained in the cassette can be measured to confirm that the drugs has been taken out or forgotten to take out.
2. Description of the Related Art
When the present quantity of drugs (injection drugs such as ampoules or vials) arranged in a row and contained inside a cassette of a drug dispensing apparatus is counted, proximity sensors or light-receiving sensors of a light reflection type are disposed with the same pitch as the drug arrangement pitch and the number of sensors that detected the drug is taken as the present quantity of drugs (see, for example, patent documents 1, 2).
Furthermore, it was also suggested to print a scale with a spacing corresponding to an ampoule pitch on a belt (Conston) impelling ampoules located inside the cassette in one direction toward the outlet opening and visually determining the remaining number of ampoules by reading the scale (patent document 3).
It was also suggested to provide a weight for impelling the ampoules unidirectionally toward the outlet opening of a cassette, provide a sensor in one location of the route, and detect the decrease in the number of ampoules (patent documents 4-8). According to another suggestion, the amount of ampoules is measured by image recognition using a CCD camera (patent document 9).                Patent document 1: JP 2000-11072A        Patent document 2: JP 2001-258997A        Patent document 3: JP 2003-79701A        Patent document 4: JP 2001-258993A        Patent document 5: JP U5-86308A        Patent document 6: JP 2002-11075A        Patent document 7: JP 2001-258994A        Patent document 8: JP 2001-198193A        Patent document 9: JP 2001-198192A        